Abstract

The differential absorption lidar (DIAL) technique can be used to remotely detect the trace gases in ambient air by observing the absorption of pulsed laser radiation as it propagates through the atmosphere when the laser is tuned on and off a molecular absorption line.^1-3 This measurement depends critically on the assumed molecular absorption line strengths and widths. The purposes of the present study are to develop a CO₂ laser system^4-5 with very narrow linewidth (<50 KHz ~ 10^-6 cm^-1) and wide tunability (10 GHz ~ 0.3 cm^-1) and to obtain accurate molecular absorption line parameters for remote sensing applications in the 9-12 μm where the CO₂ laser wavelengths fall within the spectral absorption region of many pollutants in the atmosphere.

© 1991 Optical Society of America